The overall objective of this study is to determine the efect of neighborhood-level characteristics along with individual-level joint characteristics on cerebrovascular disease (CeVD) outcomes among HIV positive and negative veterans. The proposed epidemiologic strategy, which has been underutilized in HIV and CeVD research, includes multi-level analyses that incorporate a neighborhood-level characteristic (race and ethnic segregation) along with the joint efects of individual-level characteristics (HIV treatment, mood disorders, alcohol/drug abuse/dependence) in estimating the incidence of CeVD. This will be the frst study to consider neighborhood-level along with the joint efects of individual-level characteristics in HIV and CeVD research.